Folding knife



FIG. 1 is an isometric view from the upper right front of a folding knife, showing my new design;

FIG. 2 is a right side elevational view thereof, the left side elevational view being a mirror image of this view;

FIG. 3 is a top plan, or back, view thereof;

FIG. 4 is a bottom plan, or edge, view thereof;

FIG. 5 is a rear, or handle, end elevational view thereof; and,

FIG. 6 is a front, or blade, end elevational view thereof. 

The ornamental design for a folding knife, as shown and described. 